A proportional flow control valve

Abstract

The present invention relates to a proportional flow control valve, comprising: a control valve body, a proportional regulating valve assembly and a relief valve assembly arranged in parallel at the outlet end of an oil inlet oil circuit, an oil return check valve assembly connected to the proportional regulating valve assembly through an oil passage, the proportional regulating valve assembly comprising a proportional solenoid and a valve sleeve assembly, the proportional regulating valve assembly, the relief valve assembly and the oil return check valve assembly are all installed in the control valve body, the valve sleeve assembly comprising: a first valve sleeve, in which a first axial through hole is arranged; a first valve core, which is slidably installed in the first axial through hole; a first spring seat, which is fixed in the first axial through hole, and the first spring seat is provided with a first fuel through hole in the axial direction; a first spring, which is limited between the first valve core and the first spring seat; a plurality of control windows are evenly arranged in the radial direction on the first valve sleeve, and the control window is formed by a plurality of windows with different opening areas connected in sequence.

Description

Technical Field

[0001] The invention relates to the field of hydraulic technology, in particular to a proportional flow control valve. Background Art

[0002] Existing flow control valves have significant deficiencies in terms of control curve, parameter consistency, flow cut-off capability, and stability. The reasons are as follows:

[0003] The opening is a single shape, such as a triangular opening, which has better control accuracy for low flow conditions, but the entire control curve is a curve with a large rising rate, resulting in reduced control accuracy at high flow rates. The rectangular opening control is linear overall, but the control accuracy is lower under low oil supply conditions.

[0004] Factors such as component cumulative errors and system errors result in large differences in flow at maximum opening and deviations in performance parameters.

[0005] Due to limitations in machining accuracy, oil cleanliness, reliability, etc., there will be a certain gap between the sliding valve parts. Therefore, even though the proportional valve has been closed, the gap leakage will cause the oil to continue to flow to the actuator. For actuators that require no internal leakage, the ideal unloading effect cannot be achieved. For example, fuel cut-off in some diesel engine common rail systems.

[0006] The oil supply pressure of the system may fluctuate, or the system may consist of multiple actuators of the same model working in parallel. Inconsistent oil supply pressure caused by individual or pipeline differences will lead to large differences in flow output under the same control signal. In addition, the failure of the voltage stabilizing element in the system must not cause the system to experience flow interruption.

[0007] Solving the above problems will greatly improve the performance of rail pressure control in marine high-pressure common rail systems and similar applications. Summary of the invention

[0008] The purpose of the present invention is to provide a proportional flow control valve which has a simple structure, low failure rate, high reliability and fast action response. The valve is suitable for situations where high control accuracy and high flow cut-off performance are required in the starting and end areas of flow control; and suitable for situations where high consistency and reliability are required when the oil supply pressure changes greatly or multiple actuators need to work in parallel.

[0009] The technical solution of the present invention is:

[0010] The present invention provides a proportional flow control valve, comprising: a control valve body, a proportional regulating valve assembly and a relief valve assembly arranged in parallel at the outlet end of an oil inlet oil circuit, an oil return check valve assembly connected to the outlet end of the proportional regulating valve assembly through an oil passage, the proportional regulating valve assembly consisting of a detachably arranged proportional solenoid and a valve sleeve assembly, the proportional regulating valve assembly, the relief valve assembly and the oil return check valve assembly are all installed in the control valve body, and the valve sleeve assembly comprises:

[0011] A first valve sleeve, which is provided with a first axial through hole along the axial direction;

[0012] A first valve core is slidably mounted in the first axial through hole, and the first valve core is arranged toward the push rod of the proportional solenoid;

[0013] A first spring seat, which is fixed in the first axial through hole, and the first spring seat is provided with a first fuel through hole along the axial direction;

[0014] a first spring, which is limited between the first valve core and the first spring seat;

[0015] A plurality of control windows connected to the first axial through hole are evenly arranged on the outer wall of the first valve sleeve in the radial direction, and the control windows are formed by sequentially connecting a plurality of windows with different opening areas;

[0016] When the proportional electromagnet is energized, the push rod of the proportional electromagnet is pushed out, driving the first valve core to perform axial displacement to change the area of ​​the fuel passable area in the control window, and the fuel flowing in from the oil inlet oil path passes through the fuel passable area into the first axial through hole, and then flows into the oil pass through the first fuel through hole;

[0017] The overflow valve assembly is used to open when the pressure in the oil inlet circuit is greater than a first set pressure value, and part of the fuel in the oil inlet circuit overflows into the fuel tank through the oil return circuit, so that the pressure in the oil inlet circuit is maintained at a state less than or equal to the first set pressure value;

[0018] The oil return one-way valve assembly is used to open when the pressure in the oil passage is greater than a second set pressure value, so that the fuel in the oil passage passes through the oil return passage to the fuel tank;

[0019] Preferably, it also includes:

[0020] An oil outlet check valve assembly connected to the outlet end of the proportional control valve assembly through the oil passage, and the oil outlet check valve assembly is installed in the control valve body;

[0021] The oil outlet one-way valve assembly is used to open when the pressure in the oil passage is greater than a third set pressure value, so as to transmit the fuel in the oil passage to the actuator through the oil outlet passage;

[0022] The opening pressure of the oil outlet one-way valve assembly is greater than the opening pressure of the oil return one-way valve assembly.

[0023] Preferably, the relief valve assembly comprises:

[0024] a second valve sleeve, which is provided with a second axial through hole communicating with the oil inlet passage in the axial direction, and is provided with a radial through hole communicating with the second axial through hole in the radial direction;

[0025] a second valve core slidably mounted in the second axial through hole;

[0026] a second spring seat fixed in the second axial through hole;

[0027] a second spring, which is limited between the second valve core and the second spring seat;

[0028] Wherein, when the fuel pressure in the oil inlet passage is greater than the preload force of the second spring, the second valve core moves under the action of the fuel pressure in the oil inlet passage to form a first gap for the fuel to pass through with the second valve sleeve, and the fuel in the oil inlet passage overflows into the oil tank through the radial through hole after passing through the first gap;

[0029] When the fuel pressure in the oil inlet passage is less than or equal to the preload force of the second spring, a seal is formed between the second valve core and the second valve sleeve.

[0030] Preferably, the oil return one-way valve assembly comprises:

[0031] A valve body, which is provided with a third axial through hole in the axial direction and connected to the oil passage, and a throttling hole is formed at the connecting end of the third axial through hole and the oil passage;

[0032] A third valve core is slidably mounted in the third axial through hole;

[0033] A third spring seat, which is fixed in the third axial through hole, and the third spring seat is provided with a third fuel through hole along the axial direction;

[0034] a third spring, which is limited between the third valve core and the third spring seat;

[0035] When the fuel pressure in the oil passage is greater than the preload force of the third spring, the third valve core moves under the action of the fuel pressure in the oil passage to form a second gap for the fuel to pass through with the valve body, and the fuel in the oil passage passes through the second gap and overflows through the third fuel through hole;

[0036] When the fuel pressure in the oil passage is less than or equal to the preload force of the third spring, a seal is formed between the third valve core and the valve body.

[0037] Preferably, a cavity communicating with the oil passage is formed in the control valve body, and the oil outlet one-way valve assembly includes:

[0038] a fourth valve core slidably mounted in the cavity;

[0039] a fourth spring seat, which is fixedly mounted in the cavity, and the fourth spring seat is provided with a fourth fuel through hole along the axial direction;

[0040] a fourth spring, which is limited between the fourth valve core and the fourth spring seat;

[0041] Wherein, when the fuel pressure in the oil passage is greater than the preload force of the fourth spring, the fourth valve core moves under the action of the fuel pressure in the oil passage to form a third gap for the fuel to pass through with the control valve body, and the fuel in the oil passage passes through the third gap and the fourth fuel through hole, and then flows to the actuator through the oil outlet passage;

[0042] When the fuel pressure in the oil passage is less than or equal to the preload force of the fourth spring, a seal is formed between the fourth valve core and the control valve body.

[0043] Preferably, the valve sleeve assembly further comprises:

[0044] a first adjusting gasket, which is arranged between the first spring and the first valve core;

[0045] The first elastic retaining ring is disposed around the inner wall of the first axial through hole and sleeved on the periphery of the first spring seat to limit the axial displacement of the first spring seat.

[0046] Preferably, the relief valve assembly further comprises:

[0047] a second adjusting gasket, which is arranged between the second spring and the second valve core;

[0048] The area where the second valve core and the second valve sleeve form a seal is set to be a spherical shape, and the area where the second valve sleeve and the second valve core form a seal is set to be a conical surface.

[0049] Preferably, the third valve core is a sphere made of a rigid material, and the area where the valve body and the sphere form a seal is set as a conical surface;

[0050] The third spring is a conical helical spring, and one end of the conical helical spring with a smaller diameter abuts against the sphere, and the other end with a larger diameter abuts against the third spring seat;

[0051] An interference fit is adopted between the third spring seat and the valve body.

[0052] Preferably, the oil outlet one-way valve assembly further includes:

[0053] a third adjusting gasket, which is arranged between the fourth spring and the fourth spring seat;

[0054] The second elastic retaining ring is disposed around the inner wall of the cavity and sleeved on the periphery of the fourth spring seat to limit the axial displacement of the fourth spring seat.

[0055] Preferably, the control window comprises: a first rectangular window;

[0056] a second rectangular window having an opening area greater than that of the first rectangular window;

[0057] The first rectangular window and the second rectangular window are transitionally connected via a first tapered window;

[0058] The other end of the second rectangular window is connected to a second tapered window with a gradually decreasing diameter;

[0059] The second rectangular window is arranged on a side close to the proportional electromagnet.

[0060] Preferably, the proportional flow control valve is applied to rail pressure control of a marine high pressure common rail system.

[0061] The present invention has the beneficial effects of:

[0062] The system provides pressure oil, which enters the oil inlet circuit of the proportional flow control valve, and the proportional regulating valve assembly is connected in parallel with the overflow valve assembly. When the oil inlet pressure in the oil inlet circuit exceeds the first set value, the overflow valve assembly opens to release the pressure, so that the oil inlet pressure in the oil inlet circuit remains less than or equal to the first set value, thereby stabilizing the system oil supply pressure. The pressure oil in the oil inlet circuit is regulated by the proportional regulating valve assembly and then enters the oil passage circuit. The oil in the oil passage circuit flows out through the oil return check valve assembly and the oil outlet check valve assembly. When the system is working normally, the flow rate out of the return oil check valve assembly accounts for a very small part of the system flow rate. When the proportional control valve assembly is closed, the leakage oil enters the oil passage due to the clearance between the paired parts. At this time, because the opening pressure of the oil outlet check valve assembly is higher than the opening pressure of the return oil check valve assembly, the leakage oil in the oil passage overflows through the return oil check valve assembly. The pressure of the oil passage circuit is maintained at a low value, which is much lower than the opening pressure of the oil outlet check valve assembly (i.e., the preload of the fourth spring). Therefore, the oil outlet check valve assembly cannot be opened, and its flow output is zero, achieving the purpose of cutting off the flow output. At the same time, the return oil check valve assembly has the function of preventing the return oil from flowing back, and the oil outlet check valve assembly has the function of cutting off the flow when the oil suction chamber of the actuator is under negative pressure. The proportional flow control valve controls the opening area of ​​the control window in the valve sleeve assembly through the proportional solenoid. The control window is composed of four geometric shapes of different shapes and sizes. Within the effective stroke range of the proportional solenoid, there is a unique corresponding relationship between the control current and the first valve core in the valve sleeve assembly. Since the resolution of the proportional solenoid (the minimum current that can cause the movement of the first valve core) is limited. Therefore, the control window achieves different area change rates of the control window in the same control current change interval by combining different shapes and sizes of the starting and ending intervals. The area change rate of the control window in the starting and ending intervals is smaller, the control accuracy is higher, and the flow regulation pressure is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a structural schematic diagram of the proportional flow control valve of the present invention;

[0064] Figure 2 for Figure 1 AA cross-sectional diagram of ;

[0065] Figure 3 It is a principle block diagram of the proportional flow control valve of the present invention;

[0066] Figure 4 It is a structural schematic diagram of the proportional control valve assembly of the present invention;

[0067] Figure 5 It is a structural schematic diagram of the control window of the present invention;

[0068] Figure 6 It is a curve diagram of the fuel flow rate that can pass through when different control currents are input to the proportional electromagnet in the present invention;

[0069] Figure 7 It is a structural schematic diagram of the valve sleeve assembly of the present invention;

[0070] Figure 8 It is a structural schematic diagram of the overflow valve assembly of the present invention;

[0071] Fig. 9 It is a structural schematic diagram of the oil return one-way valve assembly of the present invention;

[0072] Fig.10 It is a structural schematic diagram of the oil outlet one-way valve assembly of the present invention;

[0073] Description of the accompanying drawings: 1. control valve body; 11. cavity; 2. oil inlet circuit; 3. proportional control valve assembly; 31. proportional solenoid; 311. push rod; 312. adjusting screw; 32. valve sleeve assembly; 321. first valve sleeve; 3211. first axial through hole; 3212. control window; 3213. first rectangular window; 3214. second rectangular window; 3215. first conical window; 3216. second conical window; 322. first valve core; 323. first spring seat; 3231. first fuel through hole; 3232. second fuel through hole; 324. first spring; 325. first adjusting gasket; 326. first elastic retaining ring; 4. overflow valve assembly; 41. Second valve sleeve; 411. Second axial through hole; 412. Radial through hole; 42. Second valve core; 43. Second spring seat; 44. Second spring; 45. Second adjusting gasket; 5. Oil passage; 6. Oil return one-way valve assembly; 61. Valve body; 611. Third axial through hole; 612. Throttling hole; 62. Third valve core; 63. Third spring seat; 631. Third fuel through hole; 64. Third spring; 7. Oil outlet one-way valve assembly; 71. Fourth valve core; 72. Fourth spring seat; 721. Fourth fuel through hole; 722. Fifth fuel through hole; 73. Fourth spring; 74. Third adjusting gasket; 75. Second circlip; 8. Oil return passage; 9. Oil outlet passage. DETAILED DESCRIPTION

[0074] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0075] An embodiment of the present invention provides a proportional flow control valve, which is applied to rail pressure control of a marine high-pressure common rail system. The proportional flow control valve has a simple structure, a low failure rate, high reliability, and a fast action response. The proportional flow control valve is suitable for situations where high control accuracy and high flow cut-off performance are required in the starting and end areas of flow control; and is suitable for situations where high consistency and reliability are required when the oil supply pressure changes greatly or multiple actuators need to work in parallel.

[0076] Reference Figures 1 to 10 The control valve specifically comprises: a control valve body 1, a proportional regulating valve assembly 3 and a relief valve assembly 4 arranged in parallel at the outlet end of the oil inlet oil circuit 2, an oil return check valve assembly 6 and an oil outlet check valve assembly 7 connected to the outlet end of the proportional regulating valve assembly 3 through an oil passage 5, the proportional regulating valve assembly 3 is composed of a detachable proportional electromagnet 31 and a valve sleeve assembly 32, the purpose of the separation is to facilitate the maintenance and disassembly of the valve sleeve assembly 32 and the proportional electromagnet 31, the proportional regulating valve assembly 3, the relief valve assembly 4, the oil return check valve assembly 6 and the oil outlet check valve assembly 7 are all installed in the control valve body 1, the valve sleeve assembly 32 comprises: a first valve sleeve 321, which is provided with a first axial through hole 3211 in the axial direction; a first valve core 322, which is slidably installed in the first axial through hole 3211, and the first valve core 322 is arranged toward the push rod 311 of the proportional electromagnet 31; a first spring seat 323, which is fixed In the first axial through hole 3211, the first spring seat 323 is provided with a first fuel through hole 3231 having a larger oil passing area in the axial direction; a first spring 324 is limited between the first valve core 322 and the first spring seat 323; a plurality of control windows 3212 connected to the first axial through hole 3211 are evenly arranged on the outer wall of the first valve sleeve 321 in the radial direction, and the control window 3212 is formed by a plurality of windows with different opening areas connected in sequence; wherein, when the proportional electromagnet 31 is energized, the push rod 311 of the proportional electromagnet 31 is pushed out, driving the first valve core 322 to perform axial displacement to change the area of ​​the fuel passable area in the control window 3212, so as to achieve the purpose of regulating the flow rate, and the fuel flowing in from the oil inlet oil path 2 enters the first axial through hole 3211 through the fuel passable area, and then flows into the oil passing oil path 5 through the first fuel through hole 3231.

[0077] Among them, the fuel passable area refers to the control window 3212. Under the drive of the proportional solenoid 31, the first valve core 322 blocks the control window 3212 and the remaining part of the opening, and the fuel in the oil inlet circuit 2 can flow into the first axial through hole 3211 through the fuel passable area of ​​the control window 3212.

[0078] Combination Figure 1and Figure 4 The control window 3212 is a normally open structure, and its initial opening area can be fine-tuned according to needs by adjusting the adjustment screw 312 at the tail of the proportional electromagnet 31. After the fine-tuning is completed, the adjusting screw 312 is locked by the locking nut.

[0079] For the proportional electromagnet 31, the resolution of the proportional electromagnet 31 (i.e., the minimum current change value that can cause the axial displacement of the first valve core 322) is constant within the entire effective stroke range (for example, a current change value less than 0.01A will not cause the first valve core 322 to undergo axial displacement). In the initial state, the first spring 324 has a preload force. When the control current needs to reach 20% of the rated current, the first valve core 322 starts to move, thereby avoiding the influence of the dead zone of the proportional electromagnet 31 on the performance regulation. If the rated control current is 2A, the regulating valve will not start to move until the actual control current reaches 0.4A. For working conditions with higher control accuracy, in this embodiment, the control window 3212 is designed as a small rectangular or trapezoidal structure to achieve high-precision control, such as Figure 5 As shown, the control window 3212 is composed of four shapes of windows. Figure 6 In the control curve of the output flow, in the starting section AB and the end section DE, the flow rate changes smoothly due to the same control current, that is, the control accuracy is higher.

[0080] like Figure 5 As shown, the control window 3212 includes: a first rectangular window 3213; a second rectangular window 3214 whose opening area is larger than that of the first rectangular window 3213; the first rectangular window 3213 and the second rectangular window 3214 are transitionally connected via a first conical window 3215; the other end of the second rectangular window 3214 is connected to a second conical window 3216 with a gradually decreasing diameter; the second rectangular window 3214 is arranged on a side close to the proportional electromagnet 31. The first rectangular window 3213 and the second rectangular window 3214 are transitioned via a trapezoidal window, so that the area of ​​the fuel passable area changes smoothly during the movement of the first valve core 322, and the fuel flow rate can be more accurately controlled. Specifically, when the control current of the proportional electromagnet 31 is less than 20% of its rated current ( Figure 6 In the control current of the proportional solenoid 31, the first valve core 322 maintains the initial state. At this time, the opening area of ​​the fuel passage area of ​​the control window 3212 maintains the initial opening area, and the fuel flow rate remains unchanged. When the control current of the proportional solenoid 31 is greater than 20% of the rated current, the first valve core 322 starts to move axially under the drive of the push rod 311 of the proportional solenoid 31. Specifically, when the control current output to the proportional solenoid 31 is Figure 6In the A to B stage, the first valve core 322 is in the process of gradually covering the second conical window 3216. At this time, the opening area of ​​the fuel passing area of ​​the control window 3212 gradually decreases, and the flow rate corresponding to Figure 6 The control current output to the proportional solenoid 31 is in the A to B phase. Figure 6 In the B to C stage, the first valve core 322 is in the process of gradually covering the second rectangular window 3214. At this time, the opening area of ​​the fuel passing area of ​​the control window 3212 gradually decreases, and the flow rate corresponding to Figure 6 The control current output to the proportional solenoid 31 is in the B to C stage. Figure 6 In the C to D stage, the first valve core 322 is in the process of gradually covering the first conical window 3215. At this time, the opening area of ​​the fuel passing area of ​​the control window 3212 is gradually reduced, and the flow rate corresponding to Figure 6 The control current output to the proportional solenoid 31 is in the C to D stage. Figure 6 In the D to E stage in the figure, the first valve core 322 is in the process of gradually covering the first rectangular window 3213. At this time, the opening area of ​​the fuel passing area of ​​the control window 3212 is gradually reduced, and the flow rate corresponding to Figure 6 D to E stages.

[0081] Among them, Figure 7 As shown, in this embodiment, a second fuel through hole 3232 for allowing fuel to flow out is also provided on the outer surface of the first spring seat 323. The second fuel through hole 3232 is used to increase the oil outlet area of ​​the proportional control valve assembly 3. There are multiple second fuel through holes 3232, which are evenly distributed on the periphery of the first fuel through hole 3231.

[0082] Preferably, the valve sleeve assembly 32 further includes: a first adjustment gasket 325, which is disposed between the first spring 324 and the first valve core 322; and a first elastic retaining ring 326, which is disposed around the inner wall of the first axial through hole 3211 and sleeved on the periphery of the first spring seat 323 to limit the axial displacement of the first spring seat 323. By selecting gaskets of different thicknesses for the first adjustment gasket 325 in the valve sleeve assembly 32, the spring force of the first spring 324 is set to a required set value.

[0083] Wherein, the overflow valve assembly 4 is used to open when the pressure in the oil inlet circuit 2 is greater than the first set pressure value (the preload force of the second spring 44), and part of the fuel in the oil inlet circuit 2 overflows into the fuel tank through the return oil circuit 8, so that the pressure in the oil inlet circuit 2 is maintained at a state less than or equal to the first set pressure value (the opening pressure determined by the preload force of the second spring 44); the return oil check valve assembly 6 is used to open when the pressure in the oil passage circuit is greater than the second set pressure value (the opening pressure determined by the preload force of the third spring 64), so that the fuel in the oil passage circuit 5 passes through the return oil circuit 8 to the fuel tank; the oil outlet check valve assembly 7 is used to open when the pressure in the oil passage circuit 5 is greater than the third set pressure value (the opening pressure determined by the preload force of the fourth spring 73), so as to transmit the fuel in the oil passage circuit 5 to the actuator through the oil outlet circuit 9; the opening pressure of the oil outlet check valve assembly 7 is greater than the opening pressure of the return oil check valve assembly 6.

[0084] Preferably, refer to Figure 8 The overflow valve assembly 4 includes: a second valve sleeve 41, which is provided with a second axial through hole 411 connected to the oil inlet passage 2 in the axial direction, and a radial through hole 412 connected to the second axial through hole 411 in the radial direction; a second valve core 42, which is slidably installed in the second axial through hole 411; a second spring seat 43, which is fixed in the second axial through hole 411; and a second spring 44, which is limited between the second valve core 42 and the second spring seat 43; wherein, when the fuel pressure in the oil inlet passage 2 is greater than the preload force of the second spring 44, the second valve core 42 moves under the action of the fuel pressure in the oil inlet passage 2 to form a first gap for the fuel to pass through between the second valve sleeve 41 and the second valve sleeve 41, and the fuel in the oil inlet passage 2 overflows into the oil tank through the radial through hole 412 after passing through the first gap; when the fuel pressure in the oil inlet passage 2 is less than or equal to the preload force of the second spring 44, a seal is formed between the second valve core 42 and the second valve sleeve 41.

[0085] Preferably, if Figure 8 The overflow valve assembly 4 also includes: a second adjusting gasket 45, which is arranged between the second spring 44 and the second valve core 42; the area where the second valve core 42 and the second valve sleeve 41 form a seal is set to a spherical shape, and the area where the second valve sleeve 41 and the second valve core 42 form a seal is set to a conical surface.

[0086] In the initial state, the second spring 44 presses the second valve core 42, so that the second valve core 42 forms a seal with the second valve sleeve 41. When the fuel pressure in the oil inlet circuit 2 exceeds the first set value (the preload of the first spring 44), the second valve core 42 will open to reduce the pressure of the oil inlet circuit 2, thereby keeping the oil inlet end pressure of the proportional control valve assembly 3 within a certain range. By adjusting the second adjustment gasket 45, the opening pressure of the overflow valve assembly 4 can be adjusted. Since the overflow valve assembly 4 and the proportional control valve assembly 3 are in parallel structure, the failure of the overflow valve assembly 4 will not cause the abnormal cutoff of the oil supply of the proportional control valve assembly 3, and the actuator can continue to work, thereby making the valve more reliable.

[0087] Preferably, if Fig. 9 As shown, the oil return check valve assembly 6 includes: a valve body 61, which is provided with a third axial through hole 611 connected to the oil passage 5 in the axial direction, and a throttling hole 612 is formed at the connecting end of the third axial through hole 611 and the oil passage 5. The setting of the throttling hole 612 makes the amount of fuel entering the oil return check valve assembly 6 from the oil passage 5 very small; a third valve core 62, which is slidably installed in the third axial through hole 611; a third spring seat 63, which is fixed in the third axial through hole 611, and the third spring seat 63 is provided with a third fuel through hole 631 in the axial direction; a third The third spring 64 is limited between the third valve core 62 and the third spring seat 63; when the fuel pressure in the oil passage 5 is greater than the preload of the third spring 64, the third valve core 62 moves under the action of the fuel pressure in the oil passage 5 to form a second gap with the valve body 61 for the fuel to pass through, and the fuel in the oil passage 5 passes through the second gap and overflows through the third fuel through hole 631; when the fuel pressure in the oil passage 5 is less than or equal to the preload of the third spring 64, a seal is formed between the third valve core 62 and the valve body 61.

[0088] Preferably, the third valve core 62 is a sphere made of rigid material, and the area where the valve body 61 forms a seal with the sphere is set as a conical surface; the third spring 64 is a conical coil spring, and the end with a smaller diameter of the conical coil spring abuts the sphere, and the other end with a larger diameter abuts the third spring seat 63; an interference fit is adopted between the third spring seat 63 and the valve body 61.

[0089] When the proportional control valve assembly 3 is closed, the leakage flow enters the oil passage 5 and is relieved through the oil return one-way valve assembly 6, so that the pressure in the oil passage 5 is lower than the opening pressure of the oil outlet one-way valve assembly 7, thereby achieving the purpose of flow cutoff.

[0090] Preferably, a cavity 11 connected to the oil passage 5 is formed in the control valve body 1, and the oil outlet one-way valve assembly 7 includes: a fourth valve core 71, which is slidably installed in the cavity 11; a fourth spring seat 72, which is fixedly installed in the cavity 11, and the fourth spring seat 72 is provided with a fourth fuel through hole 721 in the axial direction; a fourth spring 73, which is limited between the fourth valve core 71 and the fourth spring seat 72; wherein, when the fuel pressure in the oil passage 5 is greater than that in the fourth spring seat 72, the fuel pressure in the oil passage 5 is greater than that in the fourth spring seat 72. When the preload force of the fourth spring 73 is applied, the fourth valve core 71 moves under the action of the fuel pressure in the oil passage 5 to form a third gap with the control valve body 1 for the fuel to pass through. After the fuel in the oil passage 5 passes through the third gap and the fourth fuel through hole 721, it flows to the actuator through the oil outlet passage 9. When the fuel pressure in the oil passage 5 is less than or equal to the preload force of the fourth spring 73, a seal is formed between the fourth valve core 71 and the control valve body 1.

[0091] like Figure 4 A plurality of evenly arranged fifth fuel holes 722 are provided on the outer circle of the fourth spring seat 72 to increase the oil outlet area.

[0092] Preferably, the oil outlet one-way valve assembly 7 also includes: a third adjusting gasket 74, which is arranged between the fourth spring 73 and the fourth spring seat 72; a second elastic retaining ring 75, which is arranged around the inner wall of the cavity 11 and is sleeved on the outer periphery of the fourth spring seat 72 to limit the axial displacement of the fourth spring seat 72.

[0093] The oil outlet one-way valve assembly 7 can be installed according to whether the actuator itself is equipped with a one-way valve or the negative pressure situation.

[0094] The working principle of the control valve mentioned above in the present application is as follows: the system provides pressure oil, which enters the oil inlet circuit 2 of the proportional flow control valve, and the proportional regulating valve assembly 3 is connected in parallel with the overflow valve assembly 4. When the oil inlet pressure in the oil inlet circuit 2 exceeds the first set value, the overflow valve assembly 3 opens to release the pressure, so that the oil inlet pressure in the oil inlet circuit 2 is maintained at a state less than or equal to the first set value, thereby stabilizing the system oil supply pressure. The pressure oil in the oil inlet circuit 2 is adjusted by the proportional regulating valve assembly 3 and enters the oil passage circuit 5. The oil in the oil passage circuit 5 flows out through the return oil check valve assembly 6 and the oil outlet check valve assembly 7. When the system is working normally, the flow rate outflowing from the return oil check valve assembly 6 accounts for a very small part of the system flow rate. When the proportional control valve assembly 3 is closed, the leakage oil enters the oil passage due to the clearance of the paired parts. At this time, because the opening pressure of the oil outlet check valve assembly 7 is higher than the opening pressure of the return oil check valve assembly 6, the leakage oil in the oil passage overflows through the return oil check valve assembly 6. The pressure of the oil passage circuit is maintained at a low value, which is much lower than the opening pressure of the oil outlet check valve assembly 7 (i.e., the preload of the fourth spring). Therefore, the oil outlet check valve assembly 7 cannot be opened, and its flow output is zero, achieving the purpose of cutting off the flow output. At the same time, the return oil check valve assembly 6 has the function of preventing the return oil from flowing back, and the oil outlet check valve assembly 7 has the function of cutting off the flow when the oil suction chamber of the actuator is under negative pressure. The proportional flow control valve controls the opening area of ​​the control window 3212 in the valve sleeve assembly 32 through the proportional solenoid 31. The control window 3212 is composed of four geometric shapes of different shapes and sizes. Within the effective stroke range of the proportional solenoid 31, there is a unique corresponding relationship between the control current and the first valve core 322 in the valve sleeve assembly 32. Since the resolution of the proportional solenoid 31 (the minimum current that can cause the first valve core 322 to move) is limited, the control window 3212 is realized by combining different shapes and sizes in the starting and ending intervals, so that in the same control current change interval, the area change rate of the control window 3212 is different. The area change rate of the control window 3212 in the starting and ending sections is smaller, the control accuracy is higher, and the flow regulation pressure is more stable.

[0095] The above embodiments only describe one or more embodiments of some of the present inventions, but it should be understood by those skilled in the art that the present invention can be implemented in many other forms without departing from its spirit and scope. Therefore, the examples and embodiments shown are considered to be illustrative rather than restrictive, and the present invention may cover various modifications and substitutions without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A proportional flow control valve, characterized in that: include: A control valve body (1), a proportional control valve assembly (3) and a relief valve assembly (4) arranged in parallel at the outlet end of an oil inlet oil circuit (2), and an oil return check valve assembly (6) connected to the outlet end of the proportional control valve assembly (3) via an oil passage (5), wherein the proportional control valve assembly (3) is composed of a detachably arranged proportional solenoid (31) and a valve sleeve assembly (32), wherein the proportional control valve assembly (3), the relief valve assembly (4) and the oil return check valve assembly (6) are all installed in the control valve body (1), and the valve sleeve assembly (32) comprises: A first valve sleeve (321), which is provided with a first axial through hole (3211) along the axial direction; a first valve core (322) slidably mounted in the first axial through hole (3211), and the first valve core (322) is arranged toward the push rod (311) of the proportional solenoid (31); A first spring seat (323) fixed in the first axial through hole (3211), the first spring seat (323) being provided with a first fuel through hole (3231) along the axial direction; a first spring (324) which is limited between the first valve core (322) and the first spring seat (323); A plurality of control windows (3212) connected to the first axial through hole (3211) are evenly arranged on the outer wall of the first valve sleeve (321) in the radial direction, and the control windows (3212) are formed by sequentially connecting a plurality of windows with different opening areas; When the proportional electromagnet (31) is energized, the push rod (311) of the proportional electromagnet (31) is pushed out, driving the first valve core (322) to perform axial displacement to change the area of ​​the fuel passable zone in the control window (3212), and the fuel flowing in from the oil inlet passage (2) enters the first axial through hole (3211) through the fuel passable zone, and then flows into the oil passage (5) through the first fuel through hole (3231); The overflow valve assembly (4) is used to open when the pressure in the oil inlet circuit (2) is greater than a first set pressure value, so that part of the fuel in the oil inlet circuit (2) overflows into the fuel tank through the oil return circuit (8), so that the pressure in the oil inlet circuit (2) is maintained at a state less than or equal to the first set pressure value; The oil return one-way valve assembly (6) is used to open when the pressure in the oil passage is greater than a second set pressure value, so that the fuel in the oil passage (5) flows into the fuel tank through the oil return passage (8); It also comprises: an oil outlet check valve assembly (7) connected to the outlet end of the proportional control valve assembly (3) through the oil passage (5), the oil outlet check valve assembly (7) being installed in the control valve body (1); The oil outlet check valve assembly (7) is used to open when the pressure in the oil passage (5) is greater than a third set pressure value, so as to transmit the fuel in the oil passage (5) to the actuator through the oil outlet passage (9); The opening pressure of the oil outlet check valve assembly (7) is greater than the opening pressure of the oil return check valve assembly (6).

2. The proportional flow control valve according to claim 1, characterized in that: The overflow valve assembly (4) comprises: A second valve sleeve (41), which is provided with a second axial through hole (411) in the axial direction and connected to the oil inlet passage (2), and is provided with a radial through hole (412) in the radial direction and connected to the second axial through hole (411); a second valve core (42) slidably mounted in the second axial through hole (411); a second spring seat (43) fixed in the second axial through hole (411); a second spring (44), which is limited between the second valve core (42) and the second spring seat (43); When the fuel pressure in the oil inlet passage (2) is greater than the preload force of the second spring (44), the second valve core (42) moves under the action of the fuel pressure in the oil inlet passage (2) to form a first gap for the fuel to pass through between the second valve core (41) and the second valve sleeve (41), and after the fuel in the oil inlet passage (2) passes through the first gap, it overflows into the oil tank through the radial through hole (412); When the fuel pressure in the oil inlet passage (2) is less than or equal to the preload force of the second spring (44), a seal is formed between the second valve core (42) and the second valve sleeve (41).

3. The proportional flow control valve according to claim 1, characterized in that: The oil return one-way valve assembly (6) comprises: A valve body (61) is provided with a third axial through hole (611) in the axial direction and connected to the oil passage (5); a throttling hole (612) is formed at the connecting end of the third axial through hole (611) and the oil passage (5); a third valve core (62) slidably mounted in the third axial through hole (611); A third spring seat (63) is fixed in the third axial through hole (611), and the third spring seat (63) is provided with a third fuel through hole (631) along the axial direction; a third spring (64), which is limited between the third valve core (62) and the third spring seat (63); When the fuel pressure in the oil passage (5) is greater than the preload force of the third spring (64), the third valve core (62) moves under the action of the fuel pressure in the oil passage (5) to form a second gap with the valve body (61) for the fuel to pass through, and the fuel in the oil passage (5) overflows through the third fuel hole (631) after passing through the second gap; When the fuel pressure in the oil passage (5) is less than or equal to the preload force of the third spring (64), a seal is formed between the third valve core (62) and the valve body (61).

4. The proportional flow control valve according to claim 1, characterized in that: The control valve body (1) has a cavity (11) formed therein and communicating with the oil passage (5). The oil outlet one-way valve assembly (7) comprises: a fourth valve core (71) slidably mounted in the cavity (11); A fourth spring seat (72) fixedly mounted in the cavity (11), and the fourth spring seat (72) is provided with a fourth fuel through hole (721) along the axial direction; a fourth spring (73), which is limited between the fourth valve core (71) and the fourth spring seat (72); When the fuel pressure in the oil passage (5) is greater than the preload force of the fourth spring (73), the fourth valve core (71) moves under the action of the fuel pressure in the oil passage (5) to form a third gap for the fuel to pass through between the fourth valve core (71) and the control valve body (1), and the fuel in the oil passage (5) passes through the third gap and the fourth fuel hole (721) and then flows to the actuator through the oil outlet passage (9); When the fuel pressure in the oil passage (5) is less than or equal to the preload force of the fourth spring (73), a seal is formed between the fourth valve core (71) and the control valve body (1).

5. The proportional flow control valve according to claim 1, characterized in that: The valve sleeve assembly (32) further comprises: a first adjusting gasket (325) disposed between the first spring (324) and the first valve core (322); A first elastic retaining ring (326) is disposed around the inner wall of the first axial through hole (3211) and sleeved on the periphery of the first spring seat (323) to limit the axial displacement of the first spring seat (323).

6. The proportional flow control valve according to claim 2, characterized in that: The overflow valve assembly (4) further comprises: a second adjusting gasket (45) disposed between the second spring (44) and the second valve core (42); The area where the second valve core (42) and the second valve sleeve (41) form a seal is configured as a spherical shape, and the area where the second valve sleeve (41) and the second valve core (42) form a seal is configured as a conical surface.

7. The proportional flow control valve according to claim 3, characterized in that: The third valve core (62) is a sphere made of a rigid material, and the area where the valve body (61) and the sphere form a seal is configured as a conical surface; The third spring (64) is a conical helical spring, and one end of the conical helical spring with a smaller diameter abuts against the sphere, while the other end with a larger diameter abuts against the third spring seat (63); An interference fit is adopted between the third spring seat (63) and the valve body (61).

8. The proportional flow control valve according to claim 4, characterized in that: The oil outlet one-way valve assembly (7) further comprises: a third adjusting gasket (74), which is arranged between the fourth spring (73) and the fourth spring seat (72); A second elastic retaining ring (75) is disposed around the inner wall of the cavity (11) and sleeved around the periphery of the fourth spring seat (72) to limit the axial displacement of the fourth spring seat (72).

9. The proportional flow control valve according to claim 1, characterized in that: The control window (3212) includes: a first rectangular window (3213); A second rectangular window (3214) having an opening area greater than that of the first rectangular window (3213); The first rectangular window (3213) and the second rectangular window (3214) are transitionally connected via a first tapered window (3215); The other end of the second rectangular window (3214) is connected to a second tapered window (3216) with a gradually decreasing diameter; The second rectangular window (3214) is arranged on a side close to the proportional electromagnet (31).

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